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NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
CONTENTS OF PRESENTATION
Introduction
Novel NiTi Films 1. One Dimensional NiTi Films 2. Gradated NiTi Films 3. NiTi (Ms1)/NiTi(Ms2) Films
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
-100 0 1000
100
200
300
Flat
Corrugated
d
Dis
plac
emen
t d
(m
)
Temperature (oC)
0.0 0.5 1.0 1.5 2.0 2.52.5
2.0
1.5
1.0
0.5
0.0
film
substrate
y/c
x/a
Corrugated Films - Complicated Stress Distribution
Report on ”Corrugated ” Film that can be easily analyzed
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Gradated Films - Not Easy to Prepare
Report on Gradated Films prepared by varying substrate temperature
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Report on “Corrugated “ Films that can be easily analyzed
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
“Geometrically Novel” NiTi Films
Film
Substrate
L
W
g
ts
tf
wf
(a) 1-D/1-D (b) 2-D/2-D (c) 1-D/2-D
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
(a) (b)
SampleNr.
Width of stripwf /m
Distance betweenstripsg /m
Aspect ratiotf/wf
Actual arealdensity
wf/(wf+g) [%]1 2.9 2.1 0.31 58.02 5.4 4.6 0.16 54.03 54 46 0.016 54.04 1000 1000 0.0009 50.0
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Principle of measurement, the cantilever deflection is determined from the change of the resonance frequency, LC1r
L
d C
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
-200 -100 0 100 200 300600
700
800
900
1000
1100
1200
1300
No
rmar
ized
def
lect
ion
(
m)
Temperature (oC)
Deflection of four differently patterned NiTi/Si bimorph cantilevers as a function of temperature. All bimorphs were processed simultaneously and identically. aspect ratio = 0.31 aspect ratio = 0.16 aspect ratio = 0.016 aspect ratio = 0.0009
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
w
fw
f
-ws-w
s
L
f
L
f
-Ls
(b)
w
s0
w
f 0
L
s < 0
L
f > 0(c)
(a)
Stress analysis of a 1-D / 2-D composite:
(a) unstressed components
(b) components stressed biaxially
(c) patterned film and substrate stressed uniaxially.
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Substrate
SMA
Conceptual martensitic microstructure:biaxially, top, and uniaxially, bottom,stressed SMA films in the two phase temperature region. The light and dark sections represent martensite and austenite, respectively.
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
)1(E
)1(E
t
t6
fs
sf2s
f'bi
0
021
021
0
0
0
0
00
00
00
00
00
000
21
00
000
00
21
0
0
0
0
0
0
00
00
000
00
00
000
21
00
00
000
21
Cantilever deflection, Stoney’s Eq.:
Martensite biaxial
Martensite uniaxial
Thermal
T
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Slope of deflection
dT
d'
T tf /wf
*)Modulus
termStrainterm
Ratio
L
'H
'
dT
d
dT
d
Esti-matedratioPest
Experi-mentalratioPexp
Low(Bi)
2s
f
t
t6
sf
fs
E
E
)1(
)1(
T
T > Af
T < As
High(Uni)
2s
f
t
t6
s
f
E
ET
s
f
1
1
0.70.84(A)0.85(M)
Low(Bi)
2s
f
t
t6
s'f
'fs
E)1(
E)1(
dT
TdM )(
As <T< Af
High(Uni)
2s
f
t
t6
s
f
E
E'
dT
TdM
)(
s
f
1
1 '
1.41.28
(avg.)
Evaluation of slopes of deflection and comparison of ratios.
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Report on Structurally Gradated Films prepared by varying substrate temperature
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Martensite/MartensiteComposite NiTi Films
Previous Experiments Show:
The nature of the martensitic transformation depends on the deposition temperature.
Therefore:
It is possible to create martensite/martensite composites by varying the substrate
temperature during deposition.
35 40 45 500
100
200
300
400
500
double layer
385 oC
250 oC
Inte
nsity
/ C
ount
s
2
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
250
385
385
385
semi-continuous
discontinuous
continuous
t [min]0 50 100
250
250
T[oC]
10
Variation of the substrate temperature during sputter deposition of the films.
top, semi-continuous,center, discontinuous,bottom, continuous
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
-150 -100 -50 0 50 100 150 200
0
2
4
6
8
10
12
14
Q-1 x
10-4
Temperature [oC]
Internal Friction of NiTi double layer film
Deposited while semi-continuously cooling, ;
Single layers deposited at250 deg C,
385 deg C,
-100 0 1000
4
8
12
-100 0 100 -100 0 1000
4
8
12
+
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Natural and Artificial Multiferroics
New UMD-based MURI
SMA/SMA Composite With Large Damping SMAs display large damping, up to 50%, at large amplitudes of vibration,
useful for mitigation of earth quake damage -scale R-M SMA Composites display 11% damping at small amplitudes,
useful for mitigation of (small amplitude) mechanical noise Craciunescu/Wuttig, J. Thin Solid Films
Rhombohedral Phase Monoclinic Phase -Scale R-M Composite
=
Temperature [C]
Dam
ping
Q-1 [
%] D
amping Q
-1 [%]
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
/g/g
21122211)2(L)1(L)0,0,0(g)2,1,(g
2120
22
/g20
21
/g2
)21(1Q
Analysis of Enhanced Damping
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
-150 -100 -50 0 50 100 150 200-100
0
100
200
300
400
500
Dis
pla
cem
ent
[ m
]
Temperature [oC]
Displacement curves of the NiTi double layer films;
Depositions on cooling; semi-continuous, discontinuous, continuous.
Depositions on heating; semi-continuous, discontinuous, continuous.
-200 -100 0 100 200
-0.03
-0.02
-0.01
0.00
M/M
Temperature [oC]
-100 0 100 200-0.015
-0.010
-0.005
0.000
0.005
M/M
Temperature [oC]
Modulus curves for the double layer film deposited on cooling and heatingleft, cooling: semi-continuous, discontinuous, continuous right, heating: semi-continuous, discontinuous, continuous
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Heating(H)
Cooling(C)
T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
Substrate
t
250oC layer385oC layer
Substrate
t
385oC layer250oC layer
Tx > Ms250, Ms385 Ms250 < Tx < Ms385 Tx < Ms250, Ms385
T
Ms385
Ms250
Tx
t
Dis
cont
inuo
us D
epos
itio
n
T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
Bimorph Temperature(Tx)
Both layers inaustenitic state
Top layer transformsunder constraint
from one side
Bottom layertransforms under
constraint from oneside
Both layers inaustenitic state
Bottom layer transformsunder constraint from
both sides
Top layer transformsunder virtually no
constraint
Deposition Type
No ModulusDefect
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Heating(H)
Cooling(C)
Substrate
t
250oCt layer
385oCt layer
Tx > any Mst Tx = Mst Tx < any Mst
Con
tinu
ous
Dep
osit
ion
Bimorph Temperature (Tx)
All t layers inaustenitic state
t layers transformcontinuously under
constraint from one side
All layers inmartensitic state
All t layers inaustenitic state
t layers transformcontinuously under
constraint fromboth sides
Top t layer transformsunder virtually no
constraint
Deposition Type
Substrate
t
385oCt layer
250oCt layer
T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
tt T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
T
Ms385
Ms250
Tx
t
t T
Ms385
Ms250
Tx
t
t
LargeDisplacement
LargeDamping
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
SUMMARY
Two Kinds of Novel NiTi Films:
1. 1-D Films;large displacement
2. Martensite/Martensite Films;large displacementlarge damping
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
COLLABORATORS
Kiyotaka MoriGrad. StudentPanasonic Res./Boston
Corneliu CraciunescuResearch Associate,U. Timisoara
Supported byOffice of Naval ResearchNational Science Foundation
NOVEL NiTi SHAPE MEMORY ALLOY FILMS
Manfred Wuttig
Manfred Wuttig Tel 301-405-5212 Fax 301-314-9467 Email wuttig@eng.umd.edu
Ehemaliger Dresdner,Anhänger des damaligen DSC: mehrmaliger Deutscher Meister, Heimat-mannschaft von Helmut Schön, des Trainers der Deutschen Fussballmannschaft.
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